The present invention relates to electronic components such as micro-relays, and in particular micro-relays, matrix relays and micro-relay chips having contacts which are opened and closed by curving a movable piece constructed of a monocrystal thin plate-shaped substrate.
Conventionally, as a relay, there has been, for example, an electromagnetic relay utilizing an electromagnet. However, the relay, which necessitates mechanical components, is hard to be reduced in size. Furthermore, the movable components of the mechanical components, which have great inertial forces, tend to disadvantageously cause fatigue failure and lack in durability.
There is otherwise existing a semiconductor switching device as a sort of small-sized relay, however, the device disadvantageously has a great resistance in turning on its contact, degraded frequency characteristics and a low insulating property between its input and output and between its terminals of an identical polarity.
In view of the aforementioned problems, the present invention has a first object to provide a subminiature micro-relay that has a small resistance in turning on its contact as well as the desired vibration resistance, frequency characteristics and insulating property.
Conventionally, as a matrix relay, there has been, for example, the one disclosed in the prior art reference of Japanese Patent Laid-Open Publication No. HEI 7-29473. The matrix relay is an electromagnet array comprised of a required number of electromagnets obtained by winding a solenoid around a fixed contact core, where the contacts are opened and closed by driving a movable spring contact provided on a strip.
However, the above-mentioned matrix relay has the electromagnet obtained by winding the solenoid around the fixed contact core as a component, and this puts a limit on compacting the device, and in particular, reduction in thickness.
Most of the components are not flat, meaning that they cannot be stacked in one direction, and this poses the problem that the assembling is troublesome and the productivity is low.
In view of the aforementioned problems, the present invention has a second object to provide a subminiature matrix relay that can be easily assembled.
Further, conventionally, as an electronic component of the micro-relay chip, there has been the one proposed in FIG. 27 and FIG. 28 of Japanese Patent Laid-Open Publication No. HEI 7-299765. That is, the electronic component is a micro-relay obtained by wire-bonding the connecting electrodes of a micro-relay chip to the external terminals of a lead frame and molding them with resin.
However, according to the above-mentioned electronic component, the whole body of the micro-relay chip has been molded with resin, and therefore, heat radiation is hard to be achieved. Therefore, due to the heat generation of the internal components, a malfunction tends to occur and the operating characteristics tend to vary.
The above-mentioned electronic component is required to individually connect by wire bonding each connecting electrode of the micro-relay chip to each external terminal formed on the lead frame. For this reason, there is a great number of working processes, and the productivity is low. Furthermore, wire disconnection tends to be caused by vibration or the like, and this poses the problem that the reliability is low.
In view of the aforementioned problems, the present invention has a third object to provide an electronic component that can prevent the malfunction and the variation in operating characteristics due to heat and has high productivity and reliability.
In order to achieve the aforementioned first object, the first feature of the present invention is a micro-relay characterized by providing a thin plate-shaped substrate comprised of a monocrystal with a driving means, supporting on a base both ends of a movable piece at least one surface of which is provided with at least one movable contact and curving the movable piece via the driving means, thereby bringing the movable contact in and out of contact with a fixed contact that faces the movable contact, for making and breaking an electric circuit.
According to the first feature of the present invention, the contacts can be opened and closed by curving the thin plate-shaped substrate constructed of the monocrystal, and therefore, the device can be easily compacted. Furthermore, the inertial force of the movable piece constructed of the thin plate-shaped substrate is small, and therefore, fatigue failure is hard to occur, so that a micro-relay having an excellent durability can be obtained.
The movable piece has its both ends supported, and therefore, a micro-relay that is hard to receive the influence of external vibration or the like and has stable operating characteristics can be obtained.
Furthermore, there can be obtained a micro-relay that has a very small resistance in turning on the contact as compared with the semiconductor switching element, high frequency characteristics and insulating properties between its input and output and between its terminals of an identical polarity.
A second feature is a micro-relay in which a device wafer is connected and integrated with an opening edge portion of a box-shaped base comprised of a handle wafer via an insulating film, and the movable piece is formed by cutting a pair of slits through the device wafer.
According to the second feature, the movable piece is formed on the device wafer connected and integrated with the box-shaped base of the handle wafer. This arrangement allows the manufacturing processes to be wholly achieved by the semiconductor manufacturing techniques.
The handle wafer and the device wafer are connected and integrated with each other via the insulating film, and therefore, the wafers can be connected and integrated with each other at a temperature lower than in directly connecting and integrating silicon objects. For this reason, a material having a low melting point can be used for the fixed contact and the movable contact, allowing the degree of freedom of design to be expanded.
A third feature is a micro-relay in which the device wafer is formed with a connecting use opening portion in a position opposite to a connecting pad of the fixed contact provided on a bottom surface of the handle wafer.
According to the third feature, connection to the outside can be achieved by utilizing wire bonding via the connecting use opening portion provided at the device wafer. This allows the wiring structure of the micro-relay itself to be simplified for easy manufacturing.
A fourth feature is a micro-relay in which the inside surface of the connecting use opening portion is covered with an insulating film.
According to the fourth feature, the inside surface of the connecting use opening portion is covered with an insulating film. Therefore, even when wire bonding is performed, the wire is not brought in contact with the silicon layer, and it is not interfered by the driving use power source.
A fifth feature is a micro-relay in which a cooling fin is formed on the upper surface of the device wafer.
According to the fifth feature, heat generated from the movable piece speedily dissipates to the outside via the cooling fin formed on the upper surface of the device wafer. This improves the operating characteristics in the restoration stage.
Even when micro-relays are integrated with each other, the cooling fin efficiently radiates heat, so that malfunction due to overheat can be prevented.
A sixth feature is a micro-relay in which the movable piece is previously curved and urged so as to bring a movable contact provided on its one surface in contact with a fixed contact that faces the movable contact.
According to the sixth feature, the thin plate-shaped substrate is previously curved to bring the movable contact in contact with the fixed contact, and therefore, a self-retaining type micro-relay can be obtained, allowing the power consumption to be remarkably reduced.
A seventh feature is a micro-relay in which a pair of pivot axes that are coaxially provided projecting roughly from a center portion between both side edge portions of the movable contact are supported on the base, one side half of the thin plate-shaped substrate is previously curved and urged upward, the remaining side half is previously curved and urged downward and the one side halves are simultaneously reversely buckled via the driving means, thereby alternately making and breaking two electric circuits.
According to the seventh feature, the one side half of the thin plate-shaped substrate can be simultaneously reversely buckled for opening and closing the contacts, and this allows the simultaneous making and breaking of a plurality of electric circuits.
An eighth feature is a micro-relay in which the driving means is a piezoelectric element laminated on one surface of the thin plate-shaped substrate.
According to the eighth feature, the movable piece is curved by the piezoelectric element, and this allows the obtainment of a micro-relay that can save the power consumption attributed to heat generation and has good energy efficiency.
A ninth feature is a micro-relay in which the driving means is a heater layer formed on one surface of the thin plate-shaped substrate.
According to the ninth feature, the movable piece is curved by only the heater layer, and this allows the obtainment of a micro-relay that necessitates a reduced number of manufacturing processes and has a high productivity.
A tenth feature is a micro-relay in which the driving means is comprised of a heater layer formed on one surface of the thin plate-shaped substrate and a driving layer formed by laminating a metal material on the heater layer via an insulating film.
According to the tenth feature, the driving layer is formed by laminating the metal material having a high coefficient of thermal expansion, and this allows the obtainment of a micro-relay that has an excellent response characteristic and a great contact pressure.
An eleventh feature is a micro-relay in which the heater layer of the driving means is comprised of a metal material such as platinum or titanium or a polysilicon laminated on the one surface of the thin plate-shaped substrate via an insulating film.
According to the eleventh feature, the heater layer is formed by laminating the metal material or polysilicon on the one surface of the thin plate-shaped substrate, and this allows the obtainment of a heater layer that has a high dimensional accuracy. Therefore, a micro-relay having uniform operating characteristics can be obtained.
A twelfth feature is a micro-relay in which the driving means is a heater section comprised of a diffused resistor formed inside the thin plate-shaped substrate.
According to the twelfth feature, the driving means is the diffused resistor formed inside the thin plate-shaped substrate made of the monocrystal. Therefore, the generated heat can be effectively utilized, allowing the obtainment of a micro-relay having a small heat loss.
A thirteenth feature is a micro-relay in which an insulating film is formed on at least one of the front surface or the rear surface of the movable piece, the surface being formed with the movable contact.
According to the thirteenth feature, the insulating film ensures the insulating property and prevents the leak of heat generated from the driving means.
A fourteenth feature is a micro-relay in which silicon compound films that are made of a silicon oxide film, a silicon nitride film or the like and have different thickness values are formed on the front and rear surfaces of the movable piece.
According to the fourteenth feature, the silicon compound film is formed on the front and rear surfaces of the movable piece, and this prevents the leak of heat generated from the movable piece, allowing the obtainment of a micro-relay having a good thermal efficiency.
A fifteenth feature is a micro-relay in which a silicon compound film comprised of a silicon oxide film, a silicon nitride film or the like for giving at least one side of the movable piece a compressive stress in proximity to a critical value at which driving starts.
According to the fifteenth feature, the compressive stress in proximity to the critical value at which driving starts can be obtained from the silicon compound film, and this allows the obtainment of a micro-relay having a good response characteristic.
A sixteenth feature is a micro-relay in which at least one adiabatic slit is formed near both end portions of the movable piece.
According to the sixteenth feature, the adiabatic slit is formed near both the end portions of the movable piece. Therefore, the heat conducting area becomes small to allow the prevention of heat conduction from both the end portions of the movable piece. As a result, the energy can be effectively utilized, thereby allowing the response characteristic to be improved.
A seventeenth feature is a micro-relay in which the adiabatic slit is filled with a polymer material having low heat conductivity.
According to the seventeenth feature, the adiabatic slit is filled with the polymer material having low heat conductivity. With this arrangement, the energy can be more effectively utilized, thereby allowing the response characteristic to be improved.
An eighteenth feature is a micro-relay in which the movable piece is extended across the base via an adiabatic silicon compound portion formed in both end portions of the movable piece.
According to the eighteenth feature, heat is hard to be conducted to the base from both the end portions of the movable piece, so that the utilization of energy and the improvement of the operating characteristics can be achieved.
A nineteenth feature is a micro-relay in which the movable piece is provided with a slit in the vicinity of the movable contact, and a pair of hinge portions for pivotally supporting the movable contact are coaxially formed.
According to the nineteenth feature, the movable contact is pivotally supported, and this eliminates the one-side hitting of the movable contact against the fixed contact and improves the contact reliability.
A twentieth feature is a micro-relay in which a root portion of the movable piece is provided with a radius for alleviating stress concentration.
According to the twentieth feature, by providing the root portion of the movable piece with the radius, the fatigue failure due to stress concentration is hard to occur, so that the operating life is prolonged.
A twenty-first feature is a micro-relay manufacturing method characterized by connecting and integrating via an insulating film a device wafer with an opening edge portion of a box-shaped base comprised of a handle wafer and thereafter cutting a pair of parallel slits through the device wafer, thereby forming a movable piece.
According to the twenty-first feature, there is the effect that a micro-relay which can be processed wholly through the semiconductor manufacturing processes and has a high dimensional accuracy can be obtained.
Furthermore, in order to achieve the aforementioned second object, a twenty-second feature of the present invention is a matrix relay characterized by providing a thin plate-shaped substrate comprised of a monocrystal with a driving means, arranging in parallel a plurality of movable pieces whose one surface is provided with a movable contact in an insulated state, fixing and supporting on a base both ends of the movable pieces, individually curving the movable pieces via the driving means, and thereby bringing the movable contact in and out of contact with a fixed contact formed on a ceiling surface of a cover positioned above the base, for making and breaking an electric circuit.
A twenty-third feature is a micro-relay in which the driving means is a piezoelectric element laminated on one surface of the thin plate-shaped substrate.
A twenty-fourth feature is a micro-relay in which the driving means is comprised of a heater layer formed on one surface of the thin plate-shaped substrate.
A twenty-fifth feature is a micro-relay in which the driving means is comprised of a heater layer formed on one surface of the thin plate-shaped substrate and a driving layer formed by laminating a metal material on the heater layer via an insulating film.
According to the twenty-second, twenty-third, twenty-fourth and twenty-fifth features of the present invention, the contacts can be opened and closed by curving the movable piece constructed of the monocrystal thin plate-shaped substrate, and this allows the easy compacting of the device.
Furthermore, since the inertial force of the movable piece is small, the fatigue failure is hard to occur and the operating life is prolonged.
Furthermore, the movable piece has its both ends fixed and supported, and this allows the obtainment of a micro-relay that is hard to receive the influence of external vibration or the like and has stable operating characteristics.
In particular, according to the twenty-fifth feature, the driving layer made of the metal material is provided, and therefore, the operating characteristics become quick, and this improves the response characteristic.
A twenty-sixth feature is a matrix relay in which the driving means is made electrically connectable on a surface of the cover via a through hole provided at the cover.
A twenty-seventh feature is a matrix relay in which the fixed contact is made electrically connectable on a front surface of the cover via a through hole provided at the cover.
According to the twenty-sixth and twenty-seventh features, the electrical connection of the internal components can be performed on the surface of the cover, and this allows the connecting work to be easy.
A twenty-eighth feature is a matrix relay in which an upper end portion of the through hole exposed to the surface of the cover is electrically connected to a connecting pad provided on the surface of the cover via a printed wiring line formed on the surface of the cover.
According to the twenty-eighth feature, the connection to the external device can be performed in the desired position via the connecting pad provided on the surface of the cover, and this has the effect of convenience.
In order to achieve the aforementioned third object, a twenty-ninth feature of the present invention is an electronic component characterized by connecting and integrating a cover made of a glass material with a base made of a silicon material and resin-molding an electronic component chip assembled with an internal component on a substructure so that the cover is coated with the mold and the bottom surface of the base is exposed.
According to the twenty-ninth feature, the bottom surface of the base made of the silicon material having a heat conductivity higher than that of the glass material is exposed to the outside of the substructure. This allows the obtainment of an electronic component that is easy to radiate heat and able to prevent the occurrence of malfunction and a variation in operating characteristics.
A thirtieth feature is an electronic component in which the internal component is electrically connected to an external terminal of the substructure via a through hole provided at the cover.
According to the thirtieth feature, there is no need for performing the individual electrical connection by wire-bonding in contrast to the prior art example, and the internal components are electrically connected to the external terminal of the substructure via the through hole provided at the cover. This arrangement makes simple connecting work, improves the productivity and improves the connection reliability. In particular, if the external terminal is formed of a lead frame, the working processes are further reduced in number, and the productivity is improved.
A thirty-first feature is an electronic component in which a heat sink is provided on the bottom surface of the base exposed to the outside of the substructure.
According to the thirty-first feature, the heat radiation efficiency via the heat sink for radiating heat is improved. This arrangement has the effect of more effectively preventing the malfunction due to heat and the variation in operating characteristics.